text: import os, unittest
  from copy import copy
  from decimal import Decimal
  from models import City, County, CountyFeat, Interstate, State, city_mapping, co_mapping, cofeat_mapping, inter_mapping
  from django.contrib.gis.db.backend import SpatialBackend
  from django.contrib.gis.utils.layermapping import LayerMapping, LayerMapError, InvalidDecimal, MissingForeignKey
  from django.contrib.gis.gdal import DataSource
  
  shp_path = os.path.dirname(__file__)
  city_shp = os.path.join(shp_path, '../data/cities/cities.shp')
  co_shp = os.path.join(shp_path, '../data/counties/counties.shp')
  inter_shp = os.path.join(shp_path, '../data/interstates/interstates.shp')
  
  # Dictionaries to hold what's expected in the county shapefile.  
  NAMES  = ['Bexar', 'Galveston', 'Harris', 'Honolulu', 'Pueblo']
  NUMS   = [1, 2, 1, 19, 1] # Number of polygons for each.                                                                                                                                                  
  STATES = ['Texas', 'Texas', 'Texas', 'Hawaii', 'Colorado']
  
  class LayerMapTest(unittest.TestCase):
  
      def test01_init(self):
          "Testing LayerMapping initialization."
  
          # Model field that does not exist.
          bad1 = copy(city_mapping)
          bad1['foobar'] = 'FooField'
  
          # Shapefile field that does not exist.
          bad2 = copy(city_mapping)
          bad2['name'] = 'Nombre'
  
          # Nonexistent geographic field type.
          bad3 = copy(city_mapping)
          bad3['point'] = 'CURVE'
  
          # Incrementing through the bad mapping dictionaries and
          # ensuring that a LayerMapError is raised.
          for bad_map in (bad1, bad2, bad3):
              try:
                  lm = LayerMapping(City, city_shp, bad_map)
              except LayerMapError:
                  pass
              else:
                  self.fail('Expected a LayerMapError.')
  
          # A LookupError should be thrown for bogus encodings.
          try:
              lm = LayerMapping(City, city_shp, city_mapping, encoding='foobar')
          except LookupError:
              pass
          else:
              self.fail('Expected a LookupError')
  
      def test02_simple_layermap(self):
          "Test LayerMapping import of a simple point shapefile."
          # Setting up for the LayerMapping.
          lm = LayerMapping(City, city_shp, city_mapping)
          lm.save()
  
          # There should be three cities in the shape file.
          self.assertEqual(3, City.objects.count())
  
          # Opening up the shapefile, and verifying the values in each
          # of the features made it to the model.
          ds = DataSource(city_shp)
          layer = ds[0]
          for feat in layer:
              city = City.objects.get(name=feat['Name'].value)
              self.assertEqual(feat['Population'].value, city.population)
              self.assertEqual(Decimal(str(feat['Density'])), city.density)
              self.assertEqual(feat['Created'].value, city.dt)
  
              # Comparing the geometries.
              pnt1, pnt2 = feat.geom, city.point
              self.assertAlmostEqual(pnt1.x, pnt2.x, 6)
              self.assertAlmostEqual(pnt1.y, pnt2.y, 6)
  
      def test03_layermap_strict(self):
          "Testing the `strict` keyword, and import of a LineString shapefile."
          # When the `strict` keyword is set an error encountered will force
          # the importation to stop.
          try:
              lm = LayerMapping(Interstate, inter_shp, inter_mapping)
              lm.save(silent=True, strict=True)
          except InvalidDecimal:
              # No transactions for geoms on MySQL; delete added features.
              if SpatialBackend.mysql: Interstate.objects.all().delete()
          else:
              self.fail('Should have failed on strict import with invalid decimal values.')
  
          # This LayerMapping should work b/c `strict` is not set.
          lm = LayerMapping(Interstate, inter_shp, inter_mapping)
          lm.save(silent=True)
  
          # Two interstate should have imported correctly.
          self.assertEqual(2, Interstate.objects.count())
          
          # Verifying the values in the layer w/the model.
          ds = DataSource(inter_shp)
  
          # Only the first two features of this shapefile are valid.
          valid_feats = ds[0][:2]
          for feat in valid_feats:
              istate = Interstate.objects.get(name=feat['Name'].value)
              
              if feat.fid == 0:
                  self.assertEqual(Decimal(str(feat['Length'])), istate.length)
              elif feat.fid == 1:
                  # Everything but the first two decimal digits were truncated,
                  # because the Interstate model's `length` field has decimal_places=2.
                  self.assertAlmostEqual(feat.get('Length'), float(istate.length), 2)
  
              for p1, p2 in zip(feat.geom, istate.path):
                  self.assertAlmostEqual(p1[0], p2[0], 6)
                  self.assertAlmostEqual(p1[1], p2[1], 6)
  
      def county_helper(self, county_feat=True):
          "Helper function for ensuring the integrity of the mapped County models."
          for name, n, st in zip(NAMES, NUMS, STATES):
              # Should only be one record b/c of `unique` keyword.
              c = County.objects.get(name=name)
              self.assertEqual(n, len(c.mpoly))
              self.assertEqual(st, c.state.name) # Checking ForeignKey mapping.
              
              # Multiple records because `unique` was not set.
              if county_feat:
                  qs = CountyFeat.objects.filter(name=name)
                  self.assertEqual(n, qs.count())
  
      def test04_layermap_unique_multigeometry_fk(self):
          "Testing the `unique`, and `transform`, geometry collection conversion, and ForeignKey mappings."
          # All the following should work.
          try:
              # Telling LayerMapping that we want no transformations performed on the data.
              lm = LayerMapping(County, co_shp, co_mapping, transform=False)
          
              # Specifying the source spatial reference system via the `source_srs` keyword.
              lm = LayerMapping(County, co_shp, co_mapping, source_srs=4269)
              lm = LayerMapping(County, co_shp, co_mapping, source_srs='NAD83')
  
              # Unique may take tuple or string parameters.
              for arg in ('name', ('name', 'mpoly')):
                  lm = LayerMapping(County, co_shp, co_mapping, transform=False, unique=arg)
          except:
              self.fail('No exception should be raised for proper use of keywords.')
              
          # Testing invalid params for the `unique` keyword.
          for e, arg in ((TypeError, 5.0), (ValueError, 'foobar'), (ValueError, ('name', 'mpolygon'))):
              self.assertRaises(e, LayerMapping, County, co_shp, co_mapping, transform=False, unique=arg)
  
          # No source reference system defined in the shapefile, should raise an error.
          if not SpatialBackend.mysql:
              self.assertRaises(LayerMapError, LayerMapping, County, co_shp, co_mapping)
  
          # Passing in invalid ForeignKey mapping parameters -- must be a dictionary
          # mapping for the model the ForeignKey points to.
          bad_fk_map1 = copy(co_mapping); bad_fk_map1['state'] = 'name'
          bad_fk_map2 = copy(co_mapping); bad_fk_map2['state'] = {'nombre' : 'State'}
          self.assertRaises(TypeError, LayerMapping, County, co_shp, bad_fk_map1, transform=False)
          self.assertRaises(LayerMapError, LayerMapping, County, co_shp, bad_fk_map2, transform=False)
  
          # There exist no State models for the ForeignKey mapping to work -- should raise
          # a MissingForeignKey exception (this error would be ignored if the `strict`
          # keyword is not set).
          lm = LayerMapping(County, co_shp, co_mapping, transform=False, unique='name')
          self.assertRaises(MissingForeignKey, lm.save, silent=True, strict=True)
  
          # Now creating the state models so the ForeignKey mapping may work.
          co, hi, tx = State(name='Colorado'), State(name='Hawaii'), State(name='Texas')
          co.save(), hi.save(), tx.save()
  
          # If a mapping is specified as a collection, all OGR fields that
          # are not collections will be converted into them.  For example,
          # a Point column would be converted to MultiPoint. Other things being done
          # w/the keyword args:
          #  `transform=False`: Specifies that no transform is to be done; this 
          #    has the effect of ignoring the spatial reference check (because the
          #    county shapefile does not have implicit spatial reference info).
          # 
          #  `unique='name'`: Creates models on the condition that they have 
          #    unique county names; geometries from each feature however will be
          #    appended to the geometry collection of the unique model.  Thus,
          #    all of the various islands in Honolulu county will be in in one
          #    database record with a MULTIPOLYGON type.
          lm = LayerMapping(County, co_shp, co_mapping, transform=False, unique='name')
          lm.save(silent=True, strict=True)
  
          # A reference that doesn't use the unique keyword; a new database record will
          # created for each polygon.
          lm = LayerMapping(CountyFeat, co_shp, cofeat_mapping, transform=False)
          lm.save(silent=True, strict=True)
  
          # The county helper is called to ensure integrity of County models.
          self.county_helper()
  
      def test05_test_fid_range_step(self):
          "Tests the `fid_range` keyword and the `step` keyword of .save()."
          # Function for clearing out all the counties before testing.
          def clear_counties(): County.objects.all().delete()
          
          # Initializing the LayerMapping object to use in these tests.
          lm = LayerMapping(County, co_shp, co_mapping, transform=False, unique='name')
  
          # Bad feature id ranges should raise a type error.
          clear_counties()
          bad_ranges = (5.0, 'foo', co_shp)
          for bad in bad_ranges:
              self.assertRaises(TypeError, lm.save, fid_range=bad)
  
          # Step keyword should not be allowed w/`fid_range`.
          fr = (3, 5) # layer[3:5]
          self.assertRaises(LayerMapError, lm.save, fid_range=fr, step=10) 
          lm.save(fid_range=fr)
          
          # Features IDs 3 & 4 are for Galveston County, Texas -- only
          # one model is returned because the `unique` keyword was set.
          qs = County.objects.all()
          self.assertEqual(1, qs.count())
          self.assertEqual('Galveston', qs[0].name)
  
          # Features IDs 5 and beyond for Honolulu County, Hawaii, and
          # FID 0 is for Pueblo County, Colorado.
          clear_counties()
          lm.save(fid_range=slice(5, None), silent=True, strict=True) # layer[5:]
          lm.save(fid_range=slice(None, 1), silent=True, strict=True) # layer[:1]
  
          # Only Pueblo & Honolulu counties should be present because of
          # the `unique` keyword.  Have to set `order_by` on this QuerySet 
          # or else MySQL will return a different ordering than the other dbs.
          qs = County.objects.order_by('name') 
          self.assertEqual(2, qs.count())
          hi, co = tuple(qs)
          hi_idx, co_idx = tuple(map(NAMES.index, ('Honolulu', 'Pueblo')))
          self.assertEqual('Pueblo', co.name); self.assertEqual(NUMS[co_idx], len(co.mpoly))
          self.assertEqual('Honolulu', hi.name); self.assertEqual(NUMS[hi_idx], len(hi.mpoly))
  
          # Testing the `step` keyword -- should get the same counties
          # regardless of we use a step that divides equally, that is odd,
          # or that is larger than the dataset.
          for st in (4,7,1000):
              clear_counties()
              lm.save(step=st, strict=True)
              self.county_helper(county_feat=False)
  
  def suite():
      s = unittest.TestSuite()
      s.addTest(unittest.makeSuite(LayerMapTest))
      return s
  